Gene analysis, for example, requires performing various biochemical processes and reactions for samples (also called analytes or specimens) obtained from living organisms and other sources, such as in extraction and amplification of nucleic acids such as DNA and RNA. Such processes and reactions require accurately mixing several reagents with the sample. In performing biochemical processes by supplying reagents to the sample, the reagents need to be delivered to cells intended for different processes.
A method that is commonly used to mix reagents is a pipetting technique that uses a dispenser robot in an auto-analysis device and other applications, as described in Patent Literature 1. The dispenser robot is a unit that works by two- or three-dimensionally driving a dispensing mechanism over a certain range of the device to automatically draw in and out liquid through a nozzle or a tip attached to the end of the dispensing mechanism.
On the other hand, PCR (Polymerase Chain Reaction) is used to amplify DNA in the field of gene analysis. For gene analysis, a template DNA needs to be PCR amplified to levels that can be detected by a detector, and PCR is known to be very effective for gene analysis.
Handling of DNA and RNA requires care not to mix the target DNA and RNA with other DNA and RNA (hereinafter, such mixing will be referred to as “contamination”). PCR involves the risk of using a trace amount of DNA (a single molecule of DNA) as a template for amplification. Contamination by other DNA, particularly PCR amplified DNA fragments (PCR products) and low-molecular clone DNA thus needs to be prevented so that these will not be used as templates. This requires performing a PCR on a clean bench by following procedures in which a chamber for handling the target DNA such as in extraction is separately provided from a chamber used for PCR, and in which a sample is transported via a sample-containing tube to prevent entry of suspended DNA in air.
The pipetting technique using a dispenser robot described in Patent Literature 1 prevents contamination by washing the nozzle or using disposable tips. However, because the nozzles and tips travel in air, it is very difficult to prevent contamination by suspended DNA in air. Patent Literature 1 attempts to minimize the possibility of contamination by performing the procedures on a clean bench with chambers separately provided for handling of DNA and PCR.
There have been studies of processes that perform extraction, purification, amplification, and analysis of biological materials in series by causing a sample to react with reagents inside a micro space using a microdevice. A microdevice has a wide range of applications, including gene analysis. Using a microdevice offers many advantages, including less consumption of samples and reagents compared to common devices, improved portability as compared to setting various reagents, and disposability. Further, because a reaction is completed within a sealed space inside a small device, microdevices are considered desirable in dealing with the contamination problem. An example of microdevice application is disclosed in Patent Literature 2, which proposes a DNA extraction technique that uses a pre-treated chip.